Left truncation in linked data: A practical guide to understanding left truncation and applying it using SAS and R.

Time-to-event data such as time to death are broadly used in medical research and drug development to understand the efficacy of a therapeutic. For time-to-event data, right censoring (data only observed up to a certain point of time) is common and easy to recognize. Methods that use right censored data, such as the Kaplan-Meier estimator and the Cox proportional hazard model, are well established. Time-to-event data can also be left truncated, which arises when patients are excluded from the sample because their events occur before a specific milestone, potentially resulting in an immortal time bias. For example, in a study evaluating the association between biomarker status and overall survival, patients who did not live long enough to receive a genomic test were not observed in the study. Left truncation causes selection bias and often leads to an overestimate of survival time. In this tutorial, we used a nationwide electronic health record-derived de-identified database to demonstrate how to analyze left truncated and right censored data without bias using example code from SAS and R.

Maternal and Infant Adverse Outcomes Associated with Mild and Severe Preeclampsia during the First Year after Delivery in the United States.

OBJECTIVE: The burden of preeclampsia severity on the health of mothers and infants during the first year after delivery is unclear, given the lack of population-based longitudinal studies in the United States. STUDY DESIGN: We assessed maternal and infant adverse outcomes during the first year after delivery using population-based hospital discharge information merged with vital statistics and birth certificates of 2,021,013 linked maternal-infant births in California. We calculated sampling weights using the National Center for Health Statistics data to adjust for observed differences in maternal characteristics between California and the rest of the United States. Separately, we estimated the association between preeclampsia and gestational age and examined collider bias in models of preeclampsia and maternal and infant adverse outcomes. RESULTS: Compared with women without preeclampsia, women with mild and severe preeclampsia delivered 0.66 weeks (95% confidence interval [CI]: 0.64, 0.68) and 2.74 weeks (95% CI: 2.72, 2.77) earlier, respectively. Mild preeclampsia was associated with an increased risk of having any maternal adverse outcome (relative risk [RR] = 1.95; 95% CI: 1.93, 1.97), as was severe preeclampsia (RR = 2.80; 95% CI: 2.78, 2.82). The risk of an infant adverse outcome was increased for severe preeclampsia (RR = 2.15; 95% CI: 2.14, 2.17) but only marginally for mild preeclampsia (RR = 0.99; 95% CI: 0.98, 1). Collider bias produced an inverse association for mild preeclampsia and attenuated the association for severe preeclampsia in models for any infant adverse outcome. CONCLUSION: Using multiple datasets, we estimated that severe preeclampsia is associated with a higher risk of maternal and infant adverse outcomes compared with mild preeclampsia, including an earlier preterm delivery.

Association of diabetes-related kidney disease with cardiovascular and non-cardiovascular outcomes: a retrospective cohort study.

BACKGROUND: Diabetes-related kidney disease is associated with end-stage renal disease and mortality, but opportunities remain to quantify its association with cardiovascular and non-cardiovascular morbidity outcomes. METHODS: We used the Truven Health MarketScan Commercial Claims and Encounters Database, 2010-2014, which includes specific health services records for employees and their dependents from a selection of large employers, health plans, and government and public organizations. We used administrative claims data to quantify the association between diabetes-related kidney disease and end-stage renal disease, myocardial infarction, congestive heart failure, stroke, and infections. Cox proportional hazard regression models were used to estimate adjusted hazard ratios of developing complications. RESULTS: Among 2.2 million patients with diabetes, 7.1% had diabetes-related kidney disease: 13.5%, stage 1-2; 33.8%, stage 3; 13.2% stages 4-5; 39.5%, unknown stage. In multivariable Cox proportional hazard models adjusted for demographic characteristics, baseline comorbid conditions, and total hospital days during the baseline period, hazard ratios for each outcome increased with greater diabetes-related kidney disease severity (stage 1-2 vs. stage 4-5) compared with no diabetes-related kidney disease: myocardial infarction, 1.2 (95% confidence interval 1.1-1.4) and 3.1 (2.9-3.4); congestive heart failure, 1.7 (1.6-1.9) and 5.6 (5.3-5.8); stroke, 1.3 (1.2-1.5) and 2.3 (2.1-2.5); infection, 1.4 (1.3-1.5) and 2.9 (2.8-3.0). Among patients with stage 4-5 disease, 36-month cumulative incidence was nearly 22.8% for congestive heart failure, and 25.8% for infections. CONCLUSIONS: Diabetes-related kidney disease appears to be formally diagnosed at a more advanced stage than might be expected, given clinical practice guidelines. Risks of cardiovascular and non-cardiovascular outcomes are high.

Short-term costs of preeclampsia to the United States health care system.

BACKGROUND: Preeclampsia is a leading cause of maternal morbidity and mortality and adverse neonatal outcomes. Little is known about the extent of the health and cost burden of preeclampsia in the United States. OBJECTIVE: This study sought to quantify the annual epidemiological and health care cost burden of preeclampsia to both mothers and infants in the United States in 2012. STUDY DESIGN: We used epidemiological and econometric methods to assess the annual cost of preeclampsia in the United States using a combination of population-based and administrative data sets: the National Center for Health Statistics Vital Statistics on Births, the California Perinatal Quality Care Collaborative Databases, the US Health Care Cost and Utilization Project database, and a commercial claims data set. RESULTS: Preeclampsia increased the probability of an adverse event from 4.6% to 10.1% for mothers and from 7.8% to 15.4% for infants while lowering gestational age by 1.7 weeks (P < .001). Overall, the total cost burden of preeclampsia during the first 12 months after birth was $1.03 billion for mothers and $1.15 billion for infants. The cost burden per infant is dependent on gestational age, ranging from $150,000 at 26 weeks gestational age to $1311 at 36 weeks gestational age. CONCLUSION: In 2012, the cost of preeclampsia within the first 12 months of delivery was $2.18 billion in the United States ($1.03 billion for mothers and $1.15 billion for infants), and was disproportionately borne by births of low gestational age.

The financial burden and health care utilization patterns associated with amnestic mild cognitive impairment.

INTRODUCTION: Individuals with amnestic mild cognitive impairment (aMCI) are at elevated risk of developing Alzheimer's disease (AD) dementia. METHODS: With data from the Aging, Demographics, and Memory Study, we used the Clinical Dementia Rating Sum of Boxes classifications to conduct a cross-sectional analysis assessing the relationship between cognitive state and various direct and indirect costs and health care utilization patterns. RESULTS: Patients with aMCI had less medical expenditures than patients with moderate and severe AD dementia (P < .001) and were also significantly less likely to have been hospitalized (P = .04) and admitted to nursing home (P < .001). Compared to individuals with normal cognition, patients with aMCI had significantly less household income (P = .018). DISCUSSION: Patients with aMCI had lower medical expenditures than patients with AD dementia. Poor cognitive status was linearly associated with lower household income, higher medical expenditures, higher likelihood of nursing and home care services, and lower likelihood of outpatient visits.

Assessing Needs for Cancer Education and Support in American Indian and Alaska Native Communities in the Northwestern United States.

American Indians and Alaska Natives (AI/ANs) experience significant cancer disparities. To inform future public health efforts, a web-based needs assessment survey collected quantitative and qualitative data from AI/AN community health workers and cancer survivors in the northwestern United States. Content analysis of qualitative responses identified themes to contextualize quantitative results. Seventy-six AI/AN respondents (93% female) described substantial unmet needs for education and resources to assist cancer survivors, including a shortage of patient navigators, support groups, and home health care workers. Fear of negative outcomes, a culturally rooted avoidance of discussing illness, and transportation difficulties were cited as major barriers to participation in cancer education and receipt of health services. Face-to-face contact was overwhelmingly preferred for community education and support, but many respondents were receptive to other communication channels, including e-mail, social media, and webinars. Survey results highlight the importance of culturally sensitive approaches to overcome barriers to cancer screening and education in AI/AN communities. Qualitative analysis revealed a widespread perception among respondents that available financial and human resources were insufficient to support AI/AN cancer patients' needs.

Validation of secondary data sources to identify Parkinson disease against clinical diagnostic criteria.

Parkinson disease (PD) is the second most common neurodegenerative disorder. Its diagnosis relies solely on a clinical examination and is not straightforward because no diagnostic test exists. Large, population-based, prospective cohort studies designed to examine other outcomes that are more common than PD might provide cost-efficient alternatives for studying the disease. However, most cohort studies have not implemented rigorous systematic screening for PD. A majority of epidemiologic studies that utilize population-based prospective designs rely on secondary data sources to identify PD cases. Direct validation of these secondary sources against clinical diagnostic criteria is lacking. The Framingham Heart Study has prospectively screened and evaluated participants for PD based on clinical diagnostic criteria. We assessed the predictive value of secondary sources for PD identification relative to clinical diagnostic criteria in the Framingham Heart Study (2001-2012). We found positive predictive values of 1.0 (95% confidence interval: 0.868, 1.0), 1.0 (95% confidence interval: 0.839, 1.0), and 0.50 (95% confidence interval: 0.307, 0.694) for PD identified from self-report, use of antiparkinsonian medications, and Medicare claims, respectively. The negative predictive values were all higher than 0.99. Our results highlight the limitations of using only Medicare claims data and suggest that population-based cohorts may be utilized for the study of PD determined via self-report or medication inventories while preserving a high degree of confidence in the validity of PD case identification.

Formulations of hormone therapy and risk of Parkinson's disease.

Hormone therapy (HT) is a class of medications widely prescribed to women in the Western world. Evidence from animal models and in vitro studies suggests that estrogen may protect against nigrostriatal system injury and increase dopamine synthesis, metabolism, and transport. Existing epidemiologic research indicates a possible reduced risk of Parkinson's disease (PD) associated with HT use. The objective of this study was to evaluate PD risk associated with specific HT formulations. Neurologist-confirmed cases and age-matched controls were identified from Group Health Cooperative (GHC) of Washington State. Final analysis included 137 female cases and 227 controls. Hormone therapy use was ascertained from the GHC pharmacy database, further classified as conjugated estrogens, esterified estrogens, and progestin. Ever use of HT formulation demonstrated a suggested elevated risk with esterified estrogen use (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.0-9.8), and no risk associated with conjugated estrogen use (OR, 0.6; 95% CI, 0.6-1.3). Restricting this analysis to prescriptions that included progestin further elevated the risk associated with esterified estrogen use (OR, 6.9; 95% CI, 2.1-22.9); again, no risk was associated with conjugated estrogen use (OR, 1.7; 95% CI, 0.6-5.0). The findings from this study suggest an increase in PD risk associated with esterified estrogen use combined with progestin, and no risk associated with conjugated estrogen with progestin. These findings could have important implications for choice of HT in clinical practice.

Enhancing case ascertainment of Parkinson's disease using Medicare claims data in a population-based cohort: the Cardiovascular Health Study.

PURPOSE: We sought to improve a previous algorithm to ascertain Parkinson's disease (PD) in the Cardiovascular Health Study by incorporating additional data from Medicare outpatient claims. We compared our results to the previous algorithm in terms of baseline prevalence and incidence of PD, as well as associations with baseline smoking characteristics. METHODS: Our original case ascertainment used self-reported diagnosis, antiparkinsonian medication, and hospitalization discharge International Classification of Diseases-Ninth version code. In this study, we incorporated additional data from fee-for-service Medicare claims, extended follow-up time, review of hospitalization records, and adjudicated cause of death. Two movement disorders specialists adjudicated final PD status. We used logistic regression models and controlled for age, sex, African American race, and education. RESULTS: We identified 75 additional cases but reclassified 80 previously identified cases as not having PD. We observed significant inverse association with smoking status (odds ratio = 0.42; 95% confidence interval (CI) = 0.22, 0.79), and inverse linear trends with pack-years (p = 0.005), and cigarettes per day (p = 0.019) with incident PD. All estimates were stronger than those from the previous algorithm. CONCLUSIONS: Our enhanced method did not alter prevalence and incidence estimates compared with our previous algorithm. However, our enhanced method provided stronger estimates of association, potentially due to reduced level of disease misclassification.

Double burden: a cross-sectional survey assessing factors associated with underweight and overweight status in Danang, Vietnam.

BACKGROUND: Many low- to middle-income countries are faced with an increasing prevalence of overweight/obesity while that for underweight remains high, a duality termed "double burden"; both are key risk factors for chronic diseases. This cross-sectional study assesses the prevalence and factors for underweight and overweight/obesity among adults in Danang, Vietnam, using WHO standard and suggested Asian-specific BMI cut-offs. METHODS: In 2010, 1713 residents age ≥ 35 years from 900 households in 6 of 56 urban, rural and mixed urban-rural communes in Danang were selected using multistage-cluster sampling methodology to participate; 1621 qualified adults enrolled. Participants completed a health survey based on WHO STEPwise Approach to Chronic Disease Risk Factor Surveillance and additional questions on chest pain and stroke symptoms. Anthropometric and other measurements were conducted. Relative risk regression was used to identify independent risk factors for underweight or overweight/obesity according to WHO standard cut-offs and suggested Asian-specific cut-offs (<18.5 kg/m2 or 23-27.49 kg/m2; and ≥ 27.5 kg/m2). RESULTS: We observed 12.4% prevalence of underweight and 16.0% for overweight/obesity using WHO standard. The prevalence of overweight/obesity doubled (33.7%) when Asian-specific cut-offs were applied. For both definitions, rural communes had the highest prevalence of underweight while urban communes had the highest prevalence of overweight/obesity. Being underweight was associated with less urbanization. Factors independently associated with being underweight included older age, rural living, current smoking, and lower systolic pressure. Factors independently associated with Asian-specific BMI definition for being overweight/obese included older age, urbanization, higher systolic pressure, and diabetes. Age was not an independent factor with WHO standard cut-offs; however, myocarial infarction and diabetes showed strong associations. CONCLUSIONS: The double burden of underweight and overweight/obesity observed in Danang is consistent with patterns found for large cities in Vietnam that are undergoing rapid economic growth and urbanization of lifestyle. Factors independently associated with underweight and overweight/obesity status by WHO standard and Asian-specific definitions include urbanization and modifiable lifestyle factors. Further studies are needed to define ethnic specific BMI cut-offs for Vietnam and to explore strategies to reduce the rising prevalence of overweight/obesity.

Predictors of functional outcome among stroke patients in Lima, Peru.

BACKGROUND: Because of the aging population in low- and middle-income countries, cerebrovascular disease is expected to remain a leading cause of death. Little has been published about stroke in Peru. We conducted a retrospective cohort study of hospitalized stroke patients at a referral center hospital in Lima, Peru to explore factors associated with functional outcome among stroke patients. METHODS: We identified 579 patients hospitalized for ischemic stroke or intracerebral hemorrhage stroke at the National Institute of Neurologic Sciences in Lima, Peru in 2008 and 2009. A favorable outcome was defined as a modified Rankin scale score of ≤ 2 at discharge. RESULTS: The mean age was 63.3 years; 75.6% had ischemic stroke; the average duration of stay was 17.3 days. At hospital discharge, 231 (39.9%) had a favorable outcome. The overall mortality rate was 5.2%. In multivariate models, the likelihood of having a favorable outcome decreased linearly with increasing age (P = .02) and increasing National Institutes of Health Stroke Scale (NIHSS) score (P = .02). Favorable outcome was also associated with male gender (relative risk [RR] 1.2; 95% confidence interval [CI] 1.0-1.5) and divorced status (RR 1.3; 95% CI 1.1-1.7). Patients on Salud Integral de Salud (SIS; public assistance-type insurance; RR 0.7; 95% CI 0.5-1.0) were also less likely to have a favorable outcome. CONCLUSIONS: Favorable outcome after stroke was independently associated with younger age, a lower NIHSS score, male gender, being divorced, and not being on SIS insurance. These findings suggest that additional study of worse functional outcomes in patients with SIS insurance be conducted and confirm the importance of risk adjustment for age, stroke severity (according to the NIHSS scale), and other socioeconomic factors in outcomes studies. Future studies should preferentially assess outcome at 30 days and 6 months to provide more reliable comparisons and allow additional study of Peruvian end-of-life decision-making and care.

Real-World Progression-Free Survival as an Endpoint in Lung Cancer: Replicating Atezolizumab and Docetaxel Arms of the OAK Trial Using Real-World Data.

Evaluating cancer treatments in real-world data (RWD) requires informative endpoints. This study replicated the atezolizumab and docetaxel arms of the OAK trial using RWD and compared progression-free survival (PFS) outcomes derived from abstracted physician's notes in RWD (rwPFS) against PFS outcomes derived from the clinical trial PFS (ctPFS). Atezolizumab and docetaxel arms of the phase III OAK randomized controlled trial (RCT; NCT02008227) were replicated in a US nationwide real-world database using selected OAK inclusion/exclusion criteria and propensity score-based adjustment for baseline prognostic variables. Concordance of outcomes was assessed using Kaplan-Meier medians and hazard ratios (HRs). The RWD cohorts comprised 133 patients on atezolizumab and 479 patients on docetaxel. After adjustment, prognostic variables were balanced between RCT arms and corresponding RWD cohorts. The rwPFS and ctPFS outcomes showed better concordance for docetaxel (2.99 vs. 3.52 months; HR: 0.99, 95% confidence interval (CI): 0.85-1.15) than for atezolizumab (3.71 vs. 2.76 months; HR: 0.8, 95% CI: 0.61-1.02). Excluding events labeled "pseudo-progression" from both RWD and RCT improved concordance for atezolizumab (4.24 vs. 4.14 months; HR: 0.95, 95% CI: 0.70-1.25). These findings were robust across sensitivity analyses. Replicating RCTs using RWD and comparing outcomes can help characterize RWD endpoints. Similarity of results between rwPFS and ctPFS at the cohort level may depend on drug category, highlighting the need for further studies to verify and understand when the corresponding outcomes can be compared, including within the same patient.

A prospective cohort study of stroke characteristics, care, and mortality in a hospital stroke registry in Vietnam.

BACKGROUND: As low and middle-income countries such as Vietnam experience the health transition from infectious to chronic diseases, the morbidity and mortality from stroke will rise. In line with the recommendation of the Institute of Medicine's report on "Promoting Cardiovascular Health in the Developing World" to "improve local data", we sought to investigate patient characteristics and clinical predictors of mortality among stroke inpatients at Da Nang Hospital in Vietnam. METHODS: A stroke registry was developed and implemented at Da Nang Hospital utilizing the World Health Organization's Stroke STEPS instrument for data collection. RESULTS: 754 patients were hospitalized for stroke from March 2010 through February 2011 and admitted to either the intensive care unit or cardiology ward. Mean age was 65 years, and 39% were female. Nearly 50% of strokes were hemorrhagic. At 28-day follow-up, 51.0% of patients with hemorrhagic stroke died whereas 20.3% of patients with ischemic stroke died. A number of factors were independently associated with 28-day mortality; the two strongest independent predictors were depressed level of consciousness on presentation and hemorrhagic stroke type. While virtually all patients completed a CT during the admission, evidence-based processes of care such as anti-thrombotic therapy and carotid ultrasound for ischemic stroke patients were underutilized. CONCLUSIONS: This cohort study highlights the high mortality due in part to the large proportion of hemorrhagic strokes in Vietnam. Lack of hypertension awareness and standards of care exacerbated clinical outcomes. Numerous opportunities for simple, inexpensive interventions to improve outcomes or reduce recurrent stroke have been identified.

Using photovoice to understand cardiovascular health awareness in Asian elders.

Photovoice, a qualitative methodology using photography by study participants, is an ideal tool for collecting information on awareness of cardiovascular health from the perspective of persons of different cultural backgrounds and English-speaking abilities who are often subject to health disparities. Participants of Chinese, Vietnamese, and Korean ethnicity were provided disposable cameras to photograph their perceptions of scenes promoting or acting as barriers to cardiovascular health. After the pictures were developed, they returned for a discussion in their native languages to contextualize the stories told in their photographs. Group facilitators spoke the respective native languages and transcribed sessions into English. Twenty-three adults participated (7 to 9 persons per ethnicity), ranging in age from 50 to 88 (mean 71.6) years; 48% were women. The photographs stimulated conversations of knowledge, beliefs, and concerns regarding heart disease and stroke. Issues surrounding food and exercise were most dominant across ethnic groups, focusing on fat and salt intake and the need to remain active. Cultural beliefs and issues of emotional health, including stress and loneliness related to living in a new country, were also depicted. Photovoice provided insight into perceptions of cardiovascular health that is vital for developing health promotion and education interventions in limited-English-speaking communities.

Replication of Overall Survival, Progression-Free Survival, and Overall Response in Chemotherapy Arms of Non-Small Cell Lung Cancer Trials Using Real-World Data.

PURPOSE: The utility of real-world data (RWD) for use as external controls in drug development is informed by studies that replicate trial control arms for different endpoints. The purpose of this study was to replicate control arms from four non-small cell lung cancer (NSCLC) randomized controlled trials (RCT) to analyze overall survival (OS), progression-free survival (PFS), and overall response rate (ORR) using RWD. PATIENTS AND METHODS: This study used RWD from a nationwide de-identified database and a clinico-genomic database to replicate OS, PFS, and ORR endpoints in the chemotherapy control arms of four first-line NSCLC RCTs evaluating atezolizumab [IMpower150-wild-type (WT), IMpower130-WT, IMpower131, and IMpower132]. Additional objectives were to develop a definition of real-world PFS (rwPFS) and to evaluate the real-world response rate (rwRR) endpoint. RESULTS: Baseline demographic and clinical characteristics were balanced after application of propensity score weighting methods. For rwPFS and OS, RWD external controls were generally similar to their RCT control counterparts. Across all four trials, the hazard ratio (HR) point estimates comparing trial controls with external controls were closer to 1.0 for the PFS endpoint than for the OS endpoint. An exploratory assessment of rwRR in RWD revealed a slight but nonsignificant overestimation of RCT ORR, which was unconfounded by baseline characteristics. CONCLUSIONS: RWD can be used to reasonably replicate the OS and PFS of chemotherapy control arms of first-line NSCLC RCTs. Additional studies can provide greater insight into the utility of RWD in drug development.

Human papillomavirus infection in female sex workers in Lima, Peru.

OBJECTIVES: To determine the prevalence and risk factors for human papillomavirus (HPV) infection in female sex workers (FSW) in Lima, Peru. METHODS: Cross-sectional study of 87 FSW. Information regarding demographics, sex work practices, and genital and blood specimens was collected. RESULTS: Forty-four (50.6%) of 87 FSW had HPV detected in cervical swabs. The prevalence of coinfection by two or more HPV types was 39.1%. Thirty-one (35.6%) were infected by at least one high-risk HPV type, representing 70.5% of women with HPV infection. HPV infection was associated with younger age but not with any demographic or sexual characteristics. CONCLUSIONS: Our study confirms the high prevalence of HPV infection in FSW reported by other groups and suggests that brothel-based FSW may be at lower risk for acquiring high-risk HPV infection.

Effectiveness of Additional Risk Minimization Measures for Atezolizumab in the European Union.

BACKGROUND: A Guide for Healthcare Professionals (HCP Guide) and patient alert card (PAC) for atezolizumab as additional risk minimization measures for physicians were distributed to raise awareness and help in the detection and management of immune-related adverse drug reactions. OBJECTIVES: The main objective of this study was to assess the receipt, knowledge, and behaviors of physicians regarding the atezolizumab HCP Guide and PAC. METHODS: A multi-country, one-wave, observational, cross-sectional, web-based, self-reported physician survey was conducted to assess the level of knowledge of key messages related to immune-related adverse drug reactions summarized in the atezolizumab HCP Guide and PAC among physicians (oncologists, pulmonologists, and urologists) prescribing atezolizumab in six European countries (Denmark, Germany, Italy, Spain, Sweden, and the UK). Responses regarding the receipt, understanding and use of the materials, and knowledge and behavior related to the HCP Guide and PAC are presented as percentages and continuous scores scaled out of 100 points, with corresponding 95% confidence intervals (CIs). RESULTS: Among 313 physicians (255 oncologists, 30 pulmonologists, and 28 urologists), 77.4% received the HCP Guide and 74.2% the PAC. The HCP Guide was read by 71.3% of the 267 physicians who received the materials, and the mean usage score was 69.5 (95% CI 66.0-72.9), and 57.1% of physicians had scores ≥ 70. The HCP Guide was completely understood by 85.4% of physicians who had read it. Mean knowledge scores were 63.9 (95% CI 62.1-65.7) and 39.4% of physicians had correct knowledge scores ≥ 70. Mean knowledge scores were 66.8 (95% CI 64.9-68.7) for receipt of both the HCP Guide and PAC, 59.4 (95% CI 55.5-63.4) for one of the materials, and 60.8 (95% CI 55.4-66.2) for having received none of the materials. Mean behavior scores were 78.9 (95% CI 76.8-81.0), and 74.8% of physicians had behavior scores ≥ 70. The mean behavior score was 79.0 (95% CI 76.5-81.5) for those who received both the HCP Guide and PAC, 76.9 (95% CI 72.2-81.5) for receipt of one of the materials, and 81.5 (95% CI 75.0-88.0) for those who received none of the materials. CONCLUSIONS: The study assessed the effectiveness of the atezolizumab additional risk minimization educational materials among physicians in six European countries, using process indicators. The educational materials reached over 70% of target physicians, 57.1% of whom reported using them. Knowledge and behavior related to immune-related adverse drug reactions for atezolizumab were no better in those who received the additional risk minimization educational materials. The results support the safe use of atezolizumab by these physician groups and contributed to the European Medicines Agency permitting removal of the HCP Guide.

Does narcolepsy symptom severity vary according to HLA-DQB1*0602 allele status?

STUDY OBJECTIVES: To investigate associations between HLA-DQB1*0602 allele status and measures of narcolepsy symptom severity. DESIGN: Cross-sectional study of population-based narcolepsy patients. SETTING: King County, Washington. PARTICIPANTS: All prevalent cases (n = 279) of physician-diagnosed narcolepsy ascertained from 2001-2005. INTERVENTIONS: N/A. MEASUREMENTS: Narcolepsy diagnosis was based on cataplexy status, diagnostic sleep study results, and chart review. The number of HLA-DQB1 alleles was determined from buccal genomic DNA. Symptom severity instruments included the Epworth Sleepiness Scale (ESS), the Ullanlinna Narcolepsy Scale (UNS), age of symptom onset, subjective sleep latency and duration, and various clinical sleep parameters. We used linear regression adjusted for African American race and an extended chi-square test of trend to assess relationships across ordered groups defined by allele number (0, 1, or 2). RESULTS: Narcolepsy patients were 63% female and 82% Caucasian, with a mean age of 47.6 years (SD = 17.1). One hundred forty-one (51%) patients had no DQB1*0602 alleles; 117 (42%) had one; and 21 (7%) had two. In the complete narcolepsy sample after adjustment for African American race, we observed a linear relationship between HLA-DQB1*0602 frequency and sleepiness as defined by the ESS (P < 0.01), narcolepsy severity as defined by UNS (P < 0.001), age of symptom onset (P < 0.05), and sleep latency (P < 0.001). In univariate analyses, HLA-DQB1*0602 frequency was also associated with napping (P < 0.05) and increased car and work accidents or near accidents (both P < 0.01). Habitual sleep duration was not associated with HLA status. These race-adjusted associations remained for the ESS (P < 0.05), UNS (P < 0.01), and sleep latency (P < 0.001) when restricting to narcolepsy with cataplexy. CONCLUSIONS: Narcolepsy symptom severity varies in a linear manner according to HLA-DQB1*0602 allele status. These findings support the notion that HLA-DQ is a disease-modifying gene.

Medical exposures in youth and the frequency of narcolepsy with cataplexy: a population-based case-control study in genetically predisposed people.

Epidemiological observations suggest that exposures in youth may trigger narcolepsy in genetically predisposed individuals. In this population-based case-control study, we sought to identify all prevalent cases of narcolepsy with cataplexy aged 18-50 years as of 1 July 2001, in King County, Washington. The 45 eligible cases who were DQB1*0602-positive were compared with 95 controls with this allele, identified through random-digit dialing and buccal smears. Cases and controls were interviewed in person about physician-diagnosed infectious and non-infectious illnesses, immunizations, head trauma and parasomnias or psychiatric problems during youth. Narcolepsy with cataplexy was more frequent in African-Americans and in poorer households. Adjusting for these factors, the condition was 5.4-fold more common [95% confidence interval (CI) = 1.5-19.1] among people reporting a physician-diagnosed strep throat before the age of 21 years. No other significant associations with childhood diseases, immunizations or head trauma were found. However, prevalence was increased 16.3-fold (95% CI = 6.1-44.1) in subjects who reported having had 'night terrors'. Strep throat may be related to narcolepsy with cataplexy in genetically susceptible individuals. The association with night terrors could simply reflect early symptoms of narcolepsy, or they could be a prodromal sign of disturbed sleep physiology.

Environmental toxins and risk of narcolepsy among people with HLA DQB1*0602.

One etiologic model for narcolepsy suggests that some environmental toxin selectively and irreversibly destroys hypocretin-producing cells in individuals with human leukocyte antigen (HLA) DQB1(*)0602. Between 2001 and 2005, the authors conducted a population-based case-control study in King County, Washington to examine narcolepsy risk in relation to toxins found in jobs, hobbies, and other non-vocational activities. Sixty-seven cases and 95 controls were enrolled; all were between ages 18 and 50 and positive for HLA DQB1(*)0602. All were administered in-person interviews about jobs, hobbies or other non-vocational activities before age 21. All analyses were adjusted for African-American race and income. Risk increased significantly for jobs involving heavy metals (odds ratio [OR]=4.7; 95% confidence interval [CI]: 1.5, 14.5) and for highest levels of exposure to woodwork (OR: 3.0; 95% CI: 1.0, 8.9), fertilizer (OR=3.1; 95% CI: 1.1, 9.1), and bug or weed killer (OR=4.5; 95% CI: 1.5, 13.4). Associations were of borderline significance for activities involving ceramics, pesticides, and painting projects. Significant dose-response relationships were evident for jobs involving metals (p<0.03), paints (p<0.03), and bug or weed killer (p<0.02). Additional studies are needed to replicate these findings and continue the search for specific toxins that could damage hypocretin neurons in genetically susceptible people.